It may seem strange to you that it is possible to look at sound. Sounds are waves in air. These waves are created by pulses of air, but waves can also be created by pulses of water. You’ve seen these at the beach and you can see them in the river that goes through the camp.  In this lesson we’ll talk about waves and how they can be described.

First, can you describe a wave?  Draw a wave below and tell me two things about them.

1. 

2.

Let's talk about something that's like a wave, your heartbeat.  Can you tell me how are the waves you drew were like your heartbeat?

1. 

2.

How many times does your heat beat in 1 minute.  Measure your heartbeat and write it down here: ________________

Can your heartbeat become stronger or weaker?  Can your heartbeat become faster or slower?  Both your heartbeat and a sound wave can be described in the same way.  Each has an amplitude (it’s either small or large) and each is a series of events through a period of time.  For instance, your heart can beat at 70 times per minute and if you stand on the beach and count the waves as they hit the shore you may count 7 waves every minute.

Tuning Forks

Sounds can be very simple.  These are called pure tones and can be created by instruments called tuning forks.  These instruments are used by piano tuners  to be certain that pianos are tuned correctly.  Listen to the tones created by the different kinds of tuning forks.

How do these forks create sounds?

The Science of Sound (Computer Application)

Now let’s see how computers can be used to learn about sound amplitude and frequency.  Then we will discover the kinds of sounds that birds make.  Write down the name of the bird whose song you think is best.

Best bird song:  __________________

When you are walking around the camp listen carefully for this call and find your bird!

Activities

Finally, let’s see if we can create our own waves with a string and then with pebbles in water.  

Something to Think About...

Draw a small amplitude wave and a large amplitude wave like you made with the string. In what way is a sound with a large amplitude wave different from a sound with a small amplitude wave?

Draw a low frequency wave and a high frequency wave like you made with the string. In what way is a sound with a high frequency wave different from a sound with a low frequency wave?

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